Asteroid 2005-YU55

AT 23:28 Greenwich Mean Time on November 8th an asteroid by the name of 2005-YU55 whizzed within 324,600km (201,700 miles) of Earth: an astronomical hair's breadth. 2005-YU55, which is 400 metres across, is a regular visitor to the Earth's neighbourhood, and this approach was its closest for 200 years. But have no fear, there is no risk of collision, at least for the next century or so (forecasting much beyond that is tricky). Instead, astronomers were delighted by the opportunity to peer at the thing. Radars scanned it (the image right is one result) and telescopes tracked its path. The next close encounter with an asteroid is not expected until 2028, when a rock called 2001-WN5 will come nearer still.